email: tony@lathes.co.uk
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Quorn Tool & Cutter Grinder
Quorn modified to sharpen gear hobs
A Manual is available for the Quorn Tool & Cutter Grinder

Long a favourite amongst model engineers - and based on the Deckel SO and SOE machines - the Quorn was designed by Professor D. H. Chaddock and available only as a kit of parts for completion at home. Today, with even well-used Deckels and Chinese-built replicas still commanding high prices, the Quorn remains an attractive proposition - though a challenging exercise to complete, even for the skilled.
Originally devised to sharpen the milling cutters necessary when building the Dore Westbury milling machine (of which Prof. Chaddock was an owner) the grinder can (without modification) also tackle lathe, shaper and planer tools, taps, reamers and twist and centre drills. With some adaptations it can also be used to modify or create special cutters - for example, those necessary when thread milling and cam forming in hard materials. Although at first sight a complex piece of apparatus it is, essentially, very simple to use and even a beginner can produce first-class results after only perfunctory practice. The secret of its success is the ability to mount a range of different wheels - while being able to present the work to them in an almost unlimited number of ways. The cutter, once mounted in a suitable collet, or held in a clamp, can be slid lengthwise under the control of a micrometer-equipped screw whilst also being rotated (oscillated or indexed) tilted and rocked in multiple planes. Degree engravings, protractor scales, setting pins, micrometer and limit stops are fitted where required and added greatly to the simplicity and ease of use.
Not only is the Quorn an amazingly useful tool, but building it an absorbing pastime, allowing the creator to produce either a utilitarian working example or one finished to the very highest cosmetic standards.
Two versions of the Quorn were made, the Mk. 1 and Mk. 2. The Mk. 2 did not supersede the Mk. 1 but incorporated a number of small improvements including the ability to fit belt and wheel guards. In 1986 Prof. Chaddock modified the design of the rotating base to eliminate the steel casting and replaced it with a fabricated component. The revised kits contained all the necessary parts, as before, together with the materials necessary to construct the new base and two additional steel blanks, one for the backplate and another for the division dial. The Mk. 1 was issued with three sheets of drawings, the Mk. 2 had four. The Quorn uses nine springs in its construction: one anti-backlash; one thimble; one index and six bearing pre-load - these originally being offered as one set, finished and ready to use.
Should you find a used Quorn without a motor (or one that is not working) it's vital to use the correct type as recommended by the designer: 1/6th h.p. running at 2,800 r.p.m. The more commonly available 1/4 h.p. 1450 r.p.m. can be used, but will need a larger pullet to get the grinding wheel speed right. Do check with the grinding wheel maker what the correct speed is and, if in doubt, scrap those provided and buy new ones (there is also the danger that, unknown to you, the wheels might have been dropped or otherwise damaged and could burst in use). Some of the units shown below have no wheel guard; if yours is the same, the writer would strongly advise making one.
A Manual is available for the Quorn Tool & Cutter Grinder

This superbly finished and equipped Quorn was photographed at an exhibition in 2007 and mounts a  rare Quorn accessory - the thread-grinding attachment. The arrangement is not dissimilar to that for thread chasing on a lathe  and uses a master thread and leader - pairs been necessary for each pitch it is desired to produce. Other non-standard features and enhancements include: damping of the motor feet with pads of  spongy material; elegant knurling on the knobs for releasing the drive belt cover, a satin finish on the ball handles and very fine rotary divisions on the column scale
Examples of the thread chasing system on a lathe can be seen here  and here

A clear view of the bronze "star wheel" on the Quorn thread-chasing attachment

A superbly finished Quorn resident in the United states

email: tony@lathes.co.uk
Home   Machine Tool Archive   Machine-tools for Sale & Wanted
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Quorn Tool & Cutter Grinder
Quorn modified to sharpen gear hobs
A Manual is available for the Quorn Tool & Cutter Grinder